New insights into cerebellar dysfunction in patients with delusional disorder: A systematic review

Introduction The cerebellum has been implicated in cognitive, affective and motor functions, including emotion regulation, executive control and sensorimotor processing. In schizophrenia, cerebellar dysfunction has been associated with treatment resistance and clinical features. However, few studies have been focused on delusional disorder (DD). Objectives Our main purpose was to review the evidence available on cerebellum abnormalities and dysfunctions in patients with DD. Methods A systematic review was conducted through PubMed, Scopus and ClinicalTrials.gov (inception-June 2022) according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) directives. The following search terms were used: cerebellum OR cerebellar AND (“delusional disorder” AND paranoia). Reference lists from included studies were hand-checked to find other potential relevant papers. Results Six studies were included from a total of 119 retrieved records (PubMed: 52, Scopus: 66, ClinicalTrials.gov: 1). Study 1:Patients with DD somatic type (n=14) presented a decreased gray matter volume in cerebellar lobules compared to healthy controls (HC) (n=32, left lobule VIIIa) and non-somatic DD (n=18, lobule V). Cerebellar volumes did not seem to differ between HC and non-somatic DD. Study 2:Abnormalities of voluntary saccadic eye movements, linking frontal and cerebellar functions, were found in DD patients (n=34) compared to HC (n=40). Study 3: Abnormal smooth pursuit eye movements in DD (n=15) compared with HC (n=40) and similar to schizophrenia (n=40). Case reports (n=3): DD associated with Dandy-Walker variant (partial vermian hypoplasia), unruptured intracerebral aneurysm of basilar artery, and megacisterna magna. Conclusions Cerebellar deficits in patients with DD has been reported, particularly in those presenting somatic delusional contents. Disclosure of Interest None Declared

Introduction: Results of a randomized controlled trial supported the efficacy of a manualized, Intensive and Brief Psychodynamic Psychotherapy (IBPP) for inpatients with severe depression, but the mechanisms by which the interaction between a psychotherapist and a patient can be involved in a process of change require more direct study. Objectives: The study aimed to explore how the psychotherapist and the patient interacted to work through the themes of focalization of their therapeutic work and how their work was part of a potential process of change.
Methods: A pragmatic case study was conducted on two cases selected from the umbrella study with one responder and one nonresponder to treatment (response defined as > 46% decrease in depressive symptoms on the MADRS). For each case, the verbatims of 6 sessions were analyzed, focusing on the themes of the IBPP manual. Results: Two main functions were revealed: 1) "Becoming the subject of one's depression", which includes the following themes: i) "Following the Tracks of Pain and Loss"; ii) "Negotiating the Distance to the Cemetery"; iii) "Beginning to Accept"; iv) "Investing in New Projects "; and 2) "Regaining a sense of support" which includes the following themes: i) "Not Being Beaten Down"; ii) "Emptying a Full Closet"; iii) "Fear of Ending Up Alone". The supportive interactions (regaining a sense of support) were present in a similar way in both cases, whereas the specific interactions (becoming the subject of one's depression) were more present in the responder case. Conclusions: In the psychotherapy of inpatients with severe depression, specific therapeutic interventions aiming to mobilize internal processes of symbolization, comprehension, and appropriation are necessary to reactivate a previously frozen mourning process. However, such interventions should be carried out in conjunction with interactions aiming to help the patient regain a sense of support. The central role of interactions that serve to build a therapeutic space and to restore epistemic trust was an unexpected result. It invites psychotherapists to pay particular attention to acknowledging a patient's melancholic suffering, and to continuously seek to adjust their interventions to foster the continuity of emotional contact and the emergence of a sense of support. Theoretical and clinical implications of these findings will be discussed.

Disclosure of Interest: None Declared
Schizophrenia and other psychotic disorders 04 EPP0505 New insights into cerebellar dysfunction in patients with delusional disorder: A systematic review Introduction: The cerebellum has been implicated in cognitive, affective and motor functions, including emotion regulation, executive control and sensorimotor processing. In schizophrenia, cerebellar dysfunction has been associated with treatment resistance and clinical features. However, few studies have been focused on delusional disorder (DD). Objectives: Our main purpose was to review the evidence available on cerebellum abnormalities and dysfunctions in patients with DD. Methods: A systematic review was conducted through PubMed, Scopus and ClinicalTrials.gov (inception-June 2022) according to the Preferred Reporting Items for Systematic Reviews and Metaanalyses (PRISMA) directives. The following search terms were used: cerebellum OR cerebellar AND ("delusional disorder" AND paranoia). Reference lists from included studies were hand-checked to find other potential relevant papers.
Results: Six studies were included from a total of 119 retrieved records (PubMed: 52, Scopus: 66, ClinicalTrials.gov: 1). Study 1: Patients with DD somatic type (n=14) presented a decreased gray matter volume in cerebellar lobules compared to healthy controls (HC) (n=32, left lobule VIIIa) and non-somatic DD (n=18, lobule V). Cerebellar volumes did not seem to differ between HC and nonsomatic DD. Study 2:Abnormalities of voluntary saccadic eye movements, linking frontal and cerebellar functions, were found in DD patients (n=34) compared to HC (n=40). Study 3: Abnormal smooth pursuit eye movements in DD (n=15) compared with HC (n=40) and similar to schizophrenia (n=40). Case reports (n=3): DD associated with Dandy-Walker variant (partial vermian hypoplasia), unruptured intracerebral aneurysm of basilar artery, and megacisterna magna. Conclusions: Cerebellar deficits in patients with DD has been reported, particularly in those presenting somatic delusional contents.  Introduction: Delusional memories or retrospective delusions have been extensively reported in subjects during or after intensive care stays. In major psychoses, authors have classically observed delusional memories impacting the prognosis and mental wellbeing. Objectives: Our aim was to review the phenomenology, psychological/biological factors contributing to delusional memories in delusional disorder (DD), and potential treatment strategies. Methods: Systematic review using PubMed, Scopus, SciELO and Web of Science electronic databases (inception-September 2022). Search terms: ("delusional memories" OR "retrospective delusions") AND ("Schizophrenia, Paranoid") [MeSH]. Studies were included if they reported psychopathology, clinical characteristics or treatment strategies of "delusional memories" in DD. Team members: AGR, JAM, MS, MB, MF, ACP, FD, MVS. Results: A total of 786 records were retrieved, including six studies. Psychogenesis:A novel cognitive neuropsychological research model (based on hypnosis) in erotomania delusions suggest a potential recall and reinterpretation of delusions beliefs in highly hypnotizable subjects. Biological basis: Frontal lobe (or executive) dysfunction does not seem to contribute to delusional memories in De Clérambault syndrome (erotomania). Phenomenology: 1)General knowledge was essentially intact, while the perceptual characteristics of delusional memories were stronger than real memories. 2)Correlations were found between delusional ideation, positive dimension of schizotypy (r=0.18), and false memories (r=0.27). 3) Jumping-to-conclusions and liberal acceptance bias influence delusional memories. Treatment:Efficacy of 1)Cognitive Behavioural Therapy (CBT) (significant reduction delusions), and 2)Metacognitive control over false memories. Conclusions: This is the first review exploring the genesis and management of delusional memories in DD. Memory deficits/ executive dysfunctions do not seem to be the only cause of this phenomenon.

EPP0507
The different effect of adverse childhood experiences on Theory of Mind brain networks in schizophrenia and healthy controls A. Pelucchi 1 *, F. Calesella 1,2 , M. Bechi 2,3 , R. Cavallaro 2,3 , S. Poletti 1,2 , B. Vai 1,2 and F. Benedetti 1,2 Introduction: Deficit in Theory of Mind (ToM) is a core feature of schizophrenia (SZ), while adverse childhood experiences (ACEs) can contribute to worsen ToM abilities through their effect on brain functioning, structure and connectivity. Objectives: Here, we investigated the effects of ACEs on brain functional connectivity (FC) during an affective and cognitive ToM task (AToM, CToM) in healthy control (HC) and SZ, and whether FC can predict the performance at the ToM task and patients' symptoms severity. Methods: The sample included 26 HC and 33 SZ. In an fMRI session, participants performed a ToM task targeting affective and cognitive domains. Whole-brain FC patterns of local correlation (LC) and multivariate pattern analysis (MVPA) were extracted. The significant MVPA clusters were used as seeds in further seed-based connectivity analyses. Second-level analyses were modelled to investigate the interaction between ACEs, the diagnosis, and the task, corrected for age, sex, and equivalent doses of chlorpromazine (p<0.05 FWE). FC values significantly affected by ACEs (Risky Family Questionnaire) were entered in a crossvalidated LASSO regression predicting symptoms severity (Positive and Negative Syndrome Scale, PANSS) and task performance measures (accuracy and response time). Results: In AToM, LC showed significant different effects of ACE between HC and SZ in frontal pole, caudate and cerebellum. MVPA showed significant widespread interaction in cortico-limbic